Transcript Air Quality Index - National Jewish Health

Air Quality Index
How Healthy is the Air You Breathe?
Air Pollution...
Definition: The presence of one or
more harmful chemicals in the
atmosphere
Air Pollution...
May cause harm to people, animals,
vegetation, or materials, or may
alter climate
Concentration (quantity) and
duration are determinants of level of
harm
How Does Air
Pollution Affect Us?
Humans breathe in 6-10 liters of air per minute
Harmful chemicals may be absorbed quickly without us being
aware
Air pollutants come into contact first with our
respiratory systems, so the lungs are most affected
by this pollution
Air pollution may also
affect the
Heart
Circulatory system
Immune system
Who Does Air
Pollution Affect?
The very young are at risk
Lungs are not fully developed until age 18
They have a faster breathing rate
The very old are at risk
May have undiagnosed lung or heart disease
Pollution can exacerbate these conditions
Persons with chronic illnesses, especially those
with respiratory, circulatory, or cardiac disease,
are also at risk
Does Air Pollution Affect
Anyone Else?
Yes, EVERYONE!
Even healthy persons
can be affected when
they exercise outdoors,
or if the concentration of
pollutants is very high
How Do We Know When the
Air is Polluted and Unsafe?
Air pollution may be colorless or odorless,
thus hard to detect
Air pollution may be obvious, as a brown or
yellow haze, or with particulates in the air
By the time pollution is obvious, it may be
at very unhealthy levels
What Causes Air
Pollution? Nature
Air pollution may occur due to natural
processes
volcanoes
dust
fires
pollen & spores
This pollution is dispersed over a wide
area, and is usually not as hazardous
as other pollution
What Else Causes
Air Pollution?
People! Air pollution may also occur
due to human activities
Called ‘anthropogenic’ sources
Stationary sources, such as power
plants or industry
Mobile sources, such as vehicles
Because it is Sometimes
Difficult to Know...
To protect public health, the Environmental
Protection Agency (EPA) monitors 5 air pollutants in
what is called the ‘Air Quality Index’ (AQI)
Ground-level Ozone (O₃)
Particulate Matter (Particle
Pollution)
< 2.5 microns
< 10 microns
Carbon Monoxide (CO)
Sulfur Dioxide (SO₂)
Nitrogen Dioxide (NO₂)
How Values to Calculate
AQI are Generated
Monitors record the average
concentration for each of the air
pollutants
The time recorded varies by pollutant
In some circumstances, models are
used to determine values for AQI
How AQI is
Calculated
An equation is used with the pollution
concentration data and an AQI break-point
table
See http://www.epa.gov/airnow/aqi_tech_assistance.pdf for details
AQI is calculated for each pollutant
The pollutant with the highest AQI
determines the level for the day, and is
noted as the responsible pollutant
AQI Values
AQI values range from 0-500
The higher the AQI, the greater the air pollution
and health concerns
An AQI of 100 corresponds to the national air
quality standard for that pollutant
A value <100 is generally considered satisfactory and not
a health hazard
A value >100 indicates air quality may be unhealthy for
some groups
A value >300 represents very hazardous air quality
What are Common
AQI Levels?
AQI levels are generally 0-100 in most U.S.
communities
AQI >100 may occur only a few times of year, if at all
Some U.S. metropolitan areas have greater pollution
and thus AQIs >100
AQIs >200 are rare in the U.S.
In other countries with dense population areas,
uncontrolled sources of pollution, and fewer
governmental emission restrictions, AQIs are frequently
>250
AQI Categories
AQI values are converted to a
category for easier
understanding by the public
Categories consider the
public health impacts of the
pollution level
A color code is used to
associate the actions to be
taken at that level
AQI Chart
AQI Reporting
Metropolitan
Statistical Areas
(MSAs) with
populations
>350,000 are
required by
Federal law to
report the AQI
daily to the
general public
AQI Distribution
AQI may be distributed:
To media
Newspapers
Radio
Television
Provided as a recorded
telephone message
Published on an Internet
site that is accessible to
the public
The AQI Report
Provides data on current day’s air quality
and may include the next’s day’s air quality
forecast
MUST include:
Reporting area
Reporting period
Critical pollutant
AQI
The AQI Report
MUST Also Include...
Information on specific health
concerns for certain populations
Descriptor must be used:
“Good” through “Hazardous”
Color Code must be noted:
“Green” through “Maroon”
Cautions for sensitive groups for
any pollutants with an AQI over 100
Pollutant Specific
Sensitive Groups
If AQI >100...
Then these sensitive groups
must be cautioned:
Ozone
People with lung disease, children, older
adults, and people who are active
outdoors
PM2.5
People with heart or lung disease,
children, and older adults
PM10
People with heart or lung disease,
children, and older adults
CO
People with heart disease
SO₂
People with asthma
Action Days
‘Action Days’ are called when the AQI is in the
unhealthy range.
Individual agencies/cities determine at what level
to call ‘Action Days’
Some use ‘Unhealthy for Sensitive Groups’ or
Code Orange
Sensitive groups should avoid prolonged or heavy outdoor
exertion outdoors
Other cities use ‘Unhealthy’ or Code Red
People should avoid prolonged or heavy outdoor exertion
outdoors
Other Preventative
Actions
High levels of AQI may trigger various
restrictions or prohibitions by local
governments to protect the public
health
Officials consider:
Current pollutant concentrations
Prevailing weather conditions
Forecasted weather conditions
Possible High
AQI Actions
Levels above 200 may cause an
“Alert” stage
Activities restricted may
include incinerator use or
open burning of leaves or
refuse
Possible High AQI Actions
Levels above 200 may cause an “Alert”
stage
Activities restricted may include incinerator use or
open burning of leaves or refuse
Levels above 300 may trigger a “Warning”
stage
Incinerator use may be prohibited, power plant
operations cut back, specific manufacturing
operations curtailed, and public driving limited with
public transportation and carpooling encouraged
AQI Emergency Actions
Levels above 400 would be an
“Emergency”
Would require most industrial and
commercial activity to cease, and
almost all private vehicle use to cease
Death would occur in some very
sensitive individuals
Sensitive individuals might be
hospitalized
Healthy persons would probably
experience symptoms that would
restrict normal activities
Seasonal Variations in
AQI
Winter
CO may be highest level pollutant
Vehicle emission control systems do not operate as well
in cold weather
Levels are generally highest during morning or evening
rush hours
Summer
VOCs and NOx form ozone more rapidly in the presence
of heat and sunlight
Levels peak in the afternoon
Smog/Ozone ‘Season’
Smog/Ozone ‘Season’ is generally
May to September
March 1- October 31 in Georgia
Ozone may not be reported in other
months unless the level is high or
the ‘season’ is longer for that area
Ozone Standards
EPA strengthened air quality
standards for ground-level ozone in
March, 2008
Ground-level ozone is a primary component
of smog
Lower levels of ozone are now
reported as unhealthy in AQI and
daily smog forecasts
Particle Pollution
Maps
Available year-round for some cities
Some state and local agencies are not
yet
participating
in this program
EPA Proposal for Stronger NO₂ Air
Quality Standards
06/29/2009 Proposal to update standards to reflect newest
findings of NO₂ exposure on public health
Propose to monitor NO₂ levels for a shorter time period
Recent research indicates that short-term exposure to high NO₂ levels,
ranging from 30 minutes to 24 hours, may increase respiratory problems,
especially in persons with asthma, children, or the elderly.
Propose to monitor within 50 meters of major roadways in cities
with at least 350,000 residents
Often a higher concentration of NO₂ near major roadways than at monitoring
stations
Proposal decision on new standard required by Jan. 22, 2010
Other Considerations
AQI levels are not the only factors in
determining how healthy the air is in a
place- other factors include:
Transportation patterns
Industrial composition
Location of monitoring
sites
Weather patterns, such as inversions
One Last Consideration...
Synergism of pollutants has not been fully
studied
Combinations of pollutants may increase harmful effects
Combinations of pollutants may cause harmful effects to
occur at lower levels
Combinations of pollutants may cause new or currently
unknown problems
EPA will likely modify the AQI as more research
is available in this area
Air Quality Index (AQI)
Summary
The AQI is:
Used to protect public health
Used to determine appropriate
activities for people, industry, and
commerce
Calculated from monitored values of 5
major pollutants
An effective tool to determine how well
Clean Air Act standards are being met
by our communities